Update on gout management: what is old and what is new

Hyperuricemia and its related diseases: mechanisms and advances in therapy

Hyperuricemia, characterized by elevated levels of serum uric acid (SUA), is linked to a spectrum of commodities such as gout, cardiovascular diseases, renal disorders, metabolic syndrome, and diabetes, etc. Significantly impairing the quality of life for those affected, the prevalence of hyperuricemia is an upward trend globally, especially in most developed countries. UA possesses a multifaceted role, such as antioxidant, pro-oxidative, pro-inflammatory, nitric oxide modulating, anti-aging, and immune effects, which are significant in both physiological and pathological contexts. The equilibrium of circulating urate levels hinges on the interplay between production and excretion, a delicate balance orchestrated by urate transporter functions across various epithelial tissues and cell types. While existing research has identified hyperuricemia involvement in numerous biological processes and signaling pathways, the precise mechanisms connecting elevated UA levels to disease etiology remain to be fully elucidated. In addition, the influence of genetic susceptibilities and environmental determinants on hyperuricemia calls for a detailed and nuanced examination. This review compiles data from global epidemiological studies and clinical practices, exploring the physiological processes and the genetic foundations of urate transporters in depth. Furthermore, we uncover the complex mechanisms by which the UA induced inflammation influences metabolic processes in individuals with hyperuricemia and the association with its relative disease, offering a foundation for innovative therapeutic approaches and advanced pharmacological strategies.

Timely Shaver Treatment Removes Chronic Tophaceous Mass Improve Surgical Outcomes

Background: Current treatments with urate-lowering therapy (ULT) are effective for most patients with gout. However, approximately 10% of these patients do not respond well to ULT and develop chronic tophus lesions. Objective: This study aimed to evaluate the efficacy of surgery involving the shaver technique against chronic tophus lesions. Methods: This single-center, retrospective cohort study included 217 patients who had cumulatively undergone 303 shaver-assisted procedures between 2002 and 2018. Surgical outcomes were assessed in terms of the length of hospital stay (LOS) and wound healing time. Results: LOS and wound healing time were longer in patients with a preoperative tophus infection and lower extremity lesions than in those without infection and with upper extremity lesions (respectively, LOS: 12.7 vs. 8.6 days; wound healing time: 22.7 vs. 16.3 days). However, factors such as age, sex, body mass index, renal function, or uricemia level exerted no significant effect on surgical outcomes. Conclusion: Surgery involving the shaver technique should be performed before tophus infection. Clinical outcomes tend to be better for upper extremity lesions than for lower extremity lesions.

Screening and characterization of potential anti-gout components from Polygonum cuspidatum by integration off-line two-dimensional liquid chromatography-mass spectrometry with affinity ultrafiltration and on-line HPLC-ABTS

Polygonum cuspidatum (P. cuspidatum) is a traditional herbal medicine with a long history and proven efficacy in treating gout. However, due to the complexity of composition and extensive content distribution, the substance basis of its anti-gout effectiveness is still unclear. A strategy was proposed via integrating off-line two-dimensional liquid chromatography (2D-LC) and targeted rapid screening technology based on ultrafiltration-liquid chromatography-mass spectrometry (UF-LC/MS) and on-line high-performance liquid chromatography-2, 2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (HPLC-ABTS) to accomplish high coverage and high throughput screening of anti-gout components from P. cuspidatum. As a result, twenty components were screened from P. cuspidatum extract with both xanthine oxidase (XOD) inhibitory activity and free radical scavenging activity, then were preliminarily identified by high-resolution electrospray ionization-quadrupole-time-of-flight mass spectrometer (ESI-Q-TOF/MS). The screened results were verified by the in vitro assays. Meanwhile, molecular docking further elucidated that the screened bioactive ingredients had favourable binding capabilities with XOD. The performance of this study can achieve high efficiency and high coverage screening of the anti-gout components from P. cuspidatum, which provides methodology and strategy support for the rapid screening of bioactive ingredients from complex medicinal plants.

Cardiovascular safety of febuxostat versus allopurinol among the Asian patients with or without gout: A systematic review and meta-analysis

The cardiovascular (CV) safety of febuxostat compared to allopurinol for the treatment of hyperuricemia among Asian patients is uncertain. In this study, we conducted a systematic review and meta-analysis to compare the CV safety profiles of febuxostat with allopurinol in Asian patients with hyperuricemia. A total of 13 studies were included. On the basis of the pooled results of cohort studies, febuxostat users were at a significantly higher risk for acute coronary syndrome (ACS; hazard ratio [HR]: 1.06, 95% confidence interval [CI]: 1.03-1.09, p < 0.01), atrial fibrillation (HR: 1.19, 95% CI: 1.05-1.35, p < 0.01) than allopurinol users, whereas no significant difference between febuxostat and allopurinol existed for urgent coronary revascularization (HR: 1.07, 95% CI: 0.98-1.16, p = 0.13), and stroke (HR: 0.96, 95% CI: 0.91-1.01, p = 0.13). Nevertheless, that difference in results of acute decompensated heart failure (ADHF; HR: 0.73, 95% CI: 0.35-1.53, p = 0.40) and all-cause death (HR = 0.86, 95% CI: 0.49-1.51, p = 0.60) was not significant based on randomized controlled trials. In the Chinese subgroup, febuxostat could increase the risk of ADHF (HR: 1.22, 95% CI: 1.01-1.48, p < 0.05), CV death (HR: 1.25, 95% CI: 1.03-1.50, p < 0.05), and all-cause mortality (HR: 1.07, 95% CI: 1.01-1.14, p < 0.05) compared to allopurinol. In conclusion, the use of febuxostat, compared with allopurinol among Asian patients, was associated with a significantly increased risk of adverse CV events.

Research progress in arthritis treatment with the active components of Herba siegesbeckiae

Arthritis is a group of diseases characterized by joint pain, swelling, stiffness, and limited movement. Osteoarthritis, rheumatoid arthritis, and gouty arthritis are the most common types of arthritis. Arthritis severely affects the quality of life of patients and imposes a heavy financial and medical burden on their families and society at large. As a widely used traditional Chinese medicine, Herba siegesbeckiae has many pharmacological effects such as anti-inflammatory and analgesic, anti-ischemic injury, cardiovascular protection, and hypoglycemic. In addition, it has significant therapeutic effects on arthritis. The rich chemical compositions of H. siegesbeckiae primarily include diterpenoids, sesquiterpenoids, and flavonoids. As one of the main active components of H. siegesbeckiae, kirenol and quercetin play a vital role in reducing arthritis symptoms. In the present study, the research progress in arthritis treatment with the active components of H. siegesbeckiae is reviewed.

A Review on the Pharmacological Aspects of Engeletin as Natural Compound

Background

Engeletin (ENG) is a natural flavonoid compound known for its diverse physiological and pharmacological effects, such as anti-inflammatory, antioxidant, and immunomodulatory properties. It has garnered significant attention as a promising candidate for drug development.

Objective

This article aims to comprehensively review the clinical application, pharmacological action, and potential mechanisms of ENG, while exploring its prospects in clinical pharmacology.

Methods

We conducted a systematic search of PubMed, Science Direct, Google Scholar, Web of Science, Scopus, and MEDLINE for a thorough review of high-quality articles on the source, extraction, and application of ENG, or the primary active ingredient for improving bodily injuries.

Results

ENG exhibits significant potential in treating a variety of diseases across different systems, attributed to its anti-inflammatory, antioxidant, anti-tumor, and metabolic regulatory activities. These effects are linked to direct or indirect interactions with multiple pathways involving key molecules upstream and downstream.

Conclusion

While ENG shows promise, its development requires further exploration. Future studies should focus on elucidating its mechanisms of action, identifying targets through clinical studies, and optimizing compounds for drug development. These research directions are crucial for advancing the development and application of flavonoids. This review underscores the significant research potential of ENG, paving the way for its application in diverse clinical settings.

Gout therapeutics and drug delivery

Gout is a common inflammatory arthritis caused by persistently elevated uric acid levels. With the improvement of people's living standards, the consumption of processed food and the widespread use of drugs that induce elevated uric acid, gout rates are increasing, seriously affecting the human quality of life, and becoming a burden to health systems worldwide. Since the pathological mechanism of gout has been elucidated, there are relatively effective drug treatments in clinical practice. However, due to (bio)pharmaceutical shortcomings of these drugs, such as poor chemical stability and limited ability to target the pathophysiological pathways, traditional drug treatment strategies show low efficacy and safety. In this scenario, drug delivery systems (DDS) design that overcome these drawbacks is urgently called for. In this review, we initially describe the pathological features, the therapeutic targets, and the drugs currently in clinical use and under investigation to treat gout. We also comprehensively summarize recent research efforts utilizing lipid, polymeric and inorganic carriers to develop advanced DDS for improved gout management and therapy.

In vitro xanthine oxidase inhibitory and in vivo anti-hyperuricemic properties of sodium kaempferol-3'-sulfonate

Xanthine oxidase (XO), a key enzyme in purine catabolism, catalyzes the oxidation of xanthine to uric acid in the body, but overproduction of uric acid may lead to hyperuricemia. This study aims to investigate in vitro XO inhibitory and in vivo anti-hyperuricemic properties of sodium kaempferol-3'-sulfonate (KS). The kinetic analysis indicates that KS is a reversible competitive inhibitor and has significant inhibitory effects on XO activity with an IC50 value of 0.338 μM. Fluorescence spectra suggested that KS could cause fluorescence quenching and conformational changes of XO due to the formation of a KS-XO complex. Molecular docking studies demonstrated that KS interacted with several amino acid residues of XO by the π-π stacking, hydrogen bonds, and hydrophobic interactions. The inhibitory mechanism of KS on XO activity might be the insertion of KS into the active site of XO to prevent the entrance of the substrate xanthine and induce conformational changes of XO. The results carried out in hyperuricemic mice showed that KS reduced serum XO activity, serum uric acid (UA), creatinine (CRE), and urea nitrogen (BUN) levels, as well as alleviating renal histopathological injury. These findings suggest that KS may be a new potent XO inhibitor against hyperuricemia-related diseases.

What are the core recommendations for gout management in first line and specialist care? Systematic review of clinical practice guidelines

BACKGROUND

Gout is the most common inflammatory arthritis, increasing in prevalence and burden. Of the rheumatic diseases, gout is the best-understood and potentially most manageable condition. However, it frequently remains untreated or poorly managed. The purpose of this systematic review is to identify Clinical Practice Guidelines (CPG) regarding gout management, evaluate their quality, and to provide a synthesis of consistent recommendations in the high-quality CPGs.

METHODS

Gout management CPGs were eligible for inclusion if they were (1) written in English and published between January 2015-February 2022; focused on adults aged ≥ 18 years of age; and met the criteria of a CPG as defined by the Institute of Medicine; and (2) were rated as high quality on the Appraisal of Guidelines for Research and Evaluation (AGREE) II instrument. Gout CPGs were excluded if they required additional payment to access; only addressed recommendations for the system/organisation of care and did not include interventional management recommendations; and/or included other arthritic conditions. OvidSP MEDLINE, Cochrane, CINAHL, Embase and Physiotherapy Evidence Database (PEDro) and four online guideline repositories were searched.

RESULTS

Six CPGs were appraised as high quality and included in the synthesis. Clinical practice guidelines consistently recommended education, commencement of non-steroidal anti-inflammatories, colchicine or corticosteroids (unless contraindicated), and assessment of cardiovascular risk factors, renal function, and co-morbid conditions for acute gout management. Consistent recommendations for chronic gout management were urate lowering therapy (ULT) and continued prophylaxis recommended based on individual patient characteristics. Clinical practice guideline recommendations were inconsistent on when to initiate ULT and length of ULT, vitamin C intake, and use of pegloticase, fenofibrate and losartan.

CONCLUSION

Management of acute gout was consistent across CPGs. Management of chronic gout was mostly consistent although there were inconsistent recommendations regarding ULT and other pharmacological therapies. This synthesis provides clear guidance that can assist health professionals to provide standardised, evidence-based gout care.

TRIAL REGISTRATION

The protocol for this review was registered with Open Science Framework (DOI https://doi.org/10.17605/OSF.IO/UB3Y7 ).

Immune and inflammatory mechanisms and therapeutic targets of gout: An update

Gout is an autoimmune disease characterized by acute or chronic inflammation and damage to bone joints induced due to the precipitation of monosodium urate (MSU) crystals. In recent years, with the continuous development of animal models and ongoing clinical investigations, more immune cells and inflammatory factors have been found to play roles in gouty inflammation. The inflammatory network involved in gout has been discovered, providing a new perspective from which to develop targeted therapy for gouty inflammation. Studies have shown that neutrophil macrophages and T lymphocytes play important roles in the pathogenesis and resolution of gout, and some inflammatory cytokines, such as those in the interleukin-1 (IL-1) family, have been shown to play anti-inflammatory or proinflammatory roles in gouty inflammation, but the mechanisms underlying their roles are unclear. In this review, we explore the roles of inflammatory cytokines, inflammasomes and immune cells in the course of gout development and the research status of therapeutic drugs used for inflammation to provide insights into future targeted therapy for gouty inflammation and the direction of gout pathogenesis research.

Could a Gout Attack Cause Non-Arteritic Anterior Ischaemic Optic Neuropathy?

Non-arteritic anterior ischaemic optic neuropathy (NAION) is a common cause of optic neuropathy in individuals over the age of 50. While risk factors such as hypertension, diabetes, and hyperlipidaemia have been identified, recent literature suggests that new risk factors may be associated with NAION. This article reports a case of NAION that occurred concurrently with an acute gout attack in a 78-year-old male patient with no other systemic diseases. We suggest that gout may be a new potential risk factor for NAION as it has the potential to cause inflammation and vascular dysfunction, particularly during acute attacks. The case emphasises the importance of considering gout as a possible risk factor in the aetiology of NAION.

The correlation between dietary inflammatory index and risk of hyperuricemia in the U.S. population

The dietary inflammatory index (DII) has been reported to be related to chronic diseases as a novel inflammatory marker. However, the correlation between DII score and hyperuricemia in adults in the United States is still unclear. Therefore, our goal was to explore the correlation between them. A total of 19,004 adults were enrolled in the National Health and Nutrition Examination Survey from 2011 to 2018. DII score was calculated according to 28 dietary items obtained by 24-hour dietary interview data. Hyperuricemia was defined by serum uric acid level. We used multilevel logistic regression models and subgroup analysis to determine whether the 2 were associated. DII scores were positively associated with serum uric acid and the risk of hyperuricemia. Per unit increased in DII score was associated with a 3 mmol/L increase in serum uric acid in males (β 3.00, 95% confidence interval (CI) 2.05-3.94) and 0.92mmol/L in females (β 0.92, 95% CI 0.07-1.77), respectively. Compared with the lowest tertile of DII score, the rise of DII grade increased the risk of hyperuricemia among the whole participants (T2: odds ratio (OR) 1.14, 95% CI 1.03, 1.27; T3: OR 1.20 [1.07, 1.34], P for trend = .0012) and males [T2: 1.15 (0.99, 1.33), T3: 1.29 (1.11, 1.50), P for trend = .0008]. For females, the correlation between DII score and hyperuricemia was statistically significant in the subgroup stratified by body mass index (BMI) (BMI < 30, OR 1.08, 95% CI 1.02-1.14, P for interaction = .0134), which indicates that the association depends on BMI. In the United States male population, the DII score has a positive correlation with hyperuricemia. Anti-inflammatory dietary intake can be beneficial for lower serum uric acid.

Modified Baihu decoction therapeutically remodels gut microbiota to inhibit acute gouty arthritis

Background: Acute gouty arthritis (AGA) is the most common first symptom of gout, and the development of gout as a metabolic and immune inflammatory disease is also correlated with the gut microbiota. However, the mechanism of the effect of changes in the gut microbiota on AGA remains unclear. The intestinal flora can not only affect purine metabolism or regulate inflammation, but also influence the therapeutic effect of drugs on AGA. The aim of this study was to investigate the exact mechanism of modified Baihu decoction (MBD) in the treatment of AGA and whether it is related to the regulation of the structure of the intestinal flora. Methods: On the 21st day of MBD administration by continuous gavage, a rat acute gouty arthritis model was constructed using sodium urate (0.1 mL/rat, 50 mg/mL), and the ankle joint swelling was measured before and 4 h, 8 h, 24 h, and 48 h after the injection of sodium urate. After 48 h of sodium urate injection, serum, liver, kidney, ankle synovial tissue and feces were collected from rats. The collected samples were examined and analyzed using H&E, Elisa, Immunohistochemistry, Histopathology, 16S rDNA, and Biochemical analysis. To investigate the mechanism of MBD to alleviate AGA using pro-inflammatory factors and intestinal flora. Results: MBD (5.84, 35 g/kg) was administered orally to AGA rats and diclofenac sodium tablets (DS-tablets) were used as standard treatment control. Serum biochemical assessment confirmed that MBD is a safe drug for the treatment of AGA. In addition, our findings confirmed that MBD relieved AGA-related symptoms, such as toe swelling. Lowering serum levels of uric acid, IL-1β, and TGF-β1 immunohistochemical results also confirmed that MBD reduced the expression of inflammatory elements such as IL-1β, NLRP3, ASC, and Caspase-1 in synovial tissue.Furthermore, compared with control group, the 16s rDNA sequencing of AGA rat faeces revealed an increase in the relative abundance of Lachnospiraceae, Muribaculaceae, and Bifidobacteriaceae species. While the relative abundance of Lactobacillaceae, Erysipelotrichaceae, Ruminococcaceae, Prevotellaceae and Enterobacteriaceae showed a relative decrease in species abundance. Of these, the reduction in species abundance of Enterobacteriaceae was associated with a reduction in amino acid metabolism and environmental perception. After MBD therapeutic intervention, the disturbance of the intestinal flora caused by AGA was restored. Conclusion: In summary, MBD is an effective agent for the treatment of AGA, with the potential mechanism being the regulation of intestinal flora to control inflammation. This would help to promote the therapeutic effect of MBD on AGA.

Association between nutrient patterns and hyperuricemia: mediation analysis involving obesity indicators in the NHANES

Background

Diet has long been hypothesized to play an important role in hyperuricemia, and weight gain is a factor that is strongly associated with the rise in serum urate. We aimed to clarify the mediating role of obesity in the relationship between diet and hyperuricemia and to determine whether a weight-loss diet is an effective way to prevent hyperuricemia.

Methods

This cross-sectional study analysed representative samples of United States (n = 20,081; NHANES 2007–2016) adults. Nutrient patterns were derived with two methods: principal component analysis (PCA) and reduced rank regression (RRR) with obesity. Logistic regression and multivariable linear regression were applied to analyse the association between nutrient patterns in obesity and hyperuricemia. Mediation analyses were used to determine whether four obesity indicators, including body mass index (BMI), waist circumference (WC), visceral adiposity index (VAI) and lipid accumulation product index (LAP), mediated the relationship between nutrient patterns and hyperuricemia.

Results

PCA revealed three nutrient patterns (including “Low energy diet”, “Lower vitamin A, C, K pattern” and “Vitamin B group”), and only Vitamin B group had a total effect on hyperuricemia. RRR revealed one main nutrient pattern associated with obesity, which was characterized by High fat and low vitamin levels and was significantly associated with hyperuricemia. Mediation analysis showed that obesity mostly or even completely mediated the relationship between nutrient patterns and hyperuricemia, especially traditional obesity indicators, which played a key intermediary effect. The proportions of indirect effects for BMI and WC were as high as 53.34 and 59.69, respectively.

Conclusions

Our findings suggest that the direct effect of diet on hyperuricemia is weak, and obesity plays a critical mediating role in the relationship between diet and hyperuricemia, which confirms that a weight-loss diet such as a “Low fat and high vitamin diet” may be useful in preventing hyperuricemia.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-14357-5.

Linear and non-linear Mendelian randomization analyses of sex-specific associations between sleep duration and hyperuricemia

Background

Observational studies have suggested a potential non-linear association between sleep duration and hyperuricemia. However, the causal nature and sex-specific differences are poorly understood. We aimed to determine the shape of sex-specific causal associations between sleep duration and hyperuricemia in the UK Biobank.

Methods

Logistic regression was used to investigate the observational association between self-reported sleep duration and hyperuricemia among 387,980 white British participants (mean age: 56.9 years and 46.0% males). Linear and non-linear Mendelian Randomization (MR) analyses were performed to assess the causal association between continuous sleep duration and hyperuricemia. The causal effects of genetically predicted short (<7 h) and long (>8 h) sleep durations on hyperuricemia were further estimated, respectively.

Results

Traditional observational analysis suggested U- and J-shaped associations between sleep duration and hyperuricemia in females and males, respectively. Linear MR did not support the causal effect of sleep duration on hyperuricemia. Non-linear MR demonstrated an approximately U-shaped causal association between continuous sleep duration and hyperuricemia in overall participants and females, but not in males. Genetically predicted short sleep duration was significantly associated with hyperuricemia in females (OR [95% CI]: 1.21 [1.08–1.36]; P = 0.001), but not in males (1.08 [0.98–1.18]; P = 0.137). By contrast, genetically predicted long sleep duration was not significantly associated with the risk of hyperuricemia in either females or males.

Conclusion

Genetically predicted short sleep duration is a potential causal risk factor for hyperuricemia for females but has little effect on males. Long sleep duration does not appear to be causally associated with hyperuricemia.